Acute Kidney Injury Gets New Focus

Healthcare leaders are stepping up efforts to diagnose and treat AKI.

This article first appeared in the July/August 2014 issue of HealthLeaders magazine.

Acute kidney injury—the sudden decline of renal function—has been underdiagnosed and, in recent years, redefined and renamed. So it's no surprise the condition often goes undetected in hospital patients, with one study estimating that AKI is diagnosed in only 13% of those affected.

The often asymptomatic condition is treatable, but linked to long-term risk for chronic kidney disease and cardiovascular problems. The push is on now to prevent it and, when that fails, catch it and treat it early. The Centers for Medicare & Medicaid Services is moving toward adding a form of AKI linked to contrast agents to its list of complications it no longer covers. Hospitals are setting up programs to screen patients identified as being at risk for the condition.

Sometimes, awareness alone can bring change. When doctors at Cincinnati Children's Hospital Medical Center—which reported patient services revenue of $1.3 billion last year—flagged signs of AKI in a select group of patients from July 2011 to June 2012, the number of days it took those patients to recover dropped by 42%.

"We didn't tell anyone to do anything else but monitor kidney function," says Stuart L. Goldstein, MD, director of the hospital's Center for Acute Care Nephrology. "We didn't tell them to change doses of antibiotics. We didn't tell them to change the prescriptions that were being used. All we did was raise awareness and identify kids at risk. The pharmacists rounding with the healthcare teams were instrumental in identifying at-risk patients and recommending daily kidney function monitoring for them." The doctors took it on themselves to take action, he says.

Once considered the unavoidable consequence of useful drugs and diagnostics, AKI is being recast as preventable and treatable. Nephrologists say risk stratification and awareness programs, like the one at Cincinnati Children's, are key. By flagging and monitoring patients most likely to lose kidney function, researchers are finding new ways to get at the underdiagnosed condition.

It's a bad one. The National Kidney Foundation reports that AKI affects 20% of all hospitalized patients and more than 45% of patients in a critical care setting. AKI, by some counts, has a 50% mortality rate, according to a study published last year in Critical Care Research and Practice.

It's not surprising the hospitalized patients are at risk of kidney injury. They often are admitted with conditions characterized by unstable cardiac status and electrolyte shifts, and are exposed to powerful contrast agents and medications, says nephrologist Alan S. Kliger, MD, vice president and chief quality officer of the Yale New Haven Health System, a three-hospital system with 2,130 licensed beds in Connecticut.

So, doctors often viewed AKI the same way they once saw catheter-associated urinary tract infections and central line–associated bloodstream infections: as inevitable complications. But over time, "culture change has led from an acceptance of the infections' perceived inevitability to real reductions in dangerous complications," Kliger says.

Clinicians, researchers, and payers are counting on bringing about the same culture change with AKI. CMS has delayed putting contrast-induced kidney injury on the list of preventable complications pending the upcoming update to the International Classification of Diseases. But organizations such as Cincinnati Children's, the Mayo Clinic, and the Hospital of the University of Pennsylvania are taking advantage of electronic medical records, risk stratification, and monitoring programs to reduce AKI.

Nephrologists don't hesitate to describe healthcare-acquired AKI as a "silent killer" or an epidemic. But for many years, they didn't quite agree on how to define the condition—or what to call it. Now what was known as acute renal failure is called acute kidney injury in an attempt to remove the suggestion that the damage is irreversible.

Over the past decade, two different groups have come up with diagnostic criteria. The most recent set of guidelines was unveiled in 2006 by a panel of kidney specialists knows as the Acute Kidney Injury Network. The approach is built around routine lab tests that measure kidney function by looking at blood levels of a chemical known as creatinine. Because the kidney filters creatinine and other waste products from the blood, high creatinine levels are a sign of reduced kidney function.

Ravindra L. Mehta, MD, associate chair for clinical research in the department of medicine and director of the acute dialysis program for the University of California San Diego Health System, was a member of that panel. Standardizing the definition and diagnostic criteria, he says, has allowed researchers to collect data on the incidence of the condition in a range of patient populations, including inpatients, outpatients, patients in and out of critical care, and those in cardiac surgery and trauma units.

In 2013, Mehta was the lead author of a study that looked at how these biomarkers were being used in clinical practice. While calling for more research, the group concluded that "the combined use of biomarkers of kidney dysfunction and damage may facilitate an earlier diagnosis of AKI, along with more accurate differential diagnosis and prognostic assessment, particularly when such markers are monitored serially over time and are combined with clinical parameters."

The consequences of ignoring signs of AKI are significant for hospitals, Mehta says, noting that changes in creatinine are associated with increased resource utilization, including length of stay, long-term and short-term mortality, and rehospitalization rates.

In adults, contrast agents used in routine imaging studies are one of the most common causes of healthcare-acquired AKI. For children, certain IV antibiotics and drug combinations can put them at risk. Dehydration and low blood pressure are risk factors, as are some chronic conditions, including heart disease, lung disease, diabetes, and preexisting chronic kidney disease.

With shifting definitions, the precise incidence of AKI has been hard to establish. A study out of Oregon Health & Science University, found AKI rates in ICU patients ranging from 20% to 50%, with contrast-induced AKI occurring on 11.5%–19% of all admissions. But the researchers noted that existing clinical studies on the exact incidence of AKI in the ICU "proved sparse" and were often complicated by varying definitions. The past decade has brought some clarity, but the researchers note that clinicians frequently underreport the incidence of AKI.

In England, British newspapers picked up on the issue after a paper published in the journal Nephrology Dialysis Transplantation reported an estimated 40,000 "excess" deaths annually in the United Kingdom, with the cost of care eating up 1% of the National Health Service budget. With these numbers in mind, the NHS has set up a nationwide Keep Kidneys Healthy program designed to "measure, educate, and manage better."

The U.K. study found that AKI prevalence in inpatients may be considerably higher than previously thought, and "up to four-fifths of cases may not be captured in routine hospital data."

Like all underdiagnosed conditions, the reported growth of AKI incidence raises the question: Are more patients developing the condition or are doctors getting better at identifying it? Stanley Goldfarb, MD—a professor of medicine at the Hospital of the University of Pennsylvania in Philadelphia, part of 1,637-licensed-bed Penn Medicine—says he wouldn't be surprised if AKI rates were increasing. But he says he thinks the change is being driven by a shift in the patient population and the sensitivity of the new diagnostic criteria.

"We're dealing with sicker and sicker older patients who are getting surgery that we never had dreamed of before," he says. "That puts them at risk for this."

A renal critical care specialist, Goldfarb has mixed feelings about the pending Medicare rule. Contrast-induced AKI is common and can't always be prevented. But he says it can be reduced if hospitals have protocols in place, and the CMS move may push hospitals in that direction. Still, such programs can take time and effort to establish, says Goldfarb, who has consulted with other hospitals on how to set up a monitoring program. For example, logistical questions emerge, such as, Should radiologists or the clinicians administer fluid that can prevent contrast-induced AKI? And, in some cases, the clinicians don't want the hospitals to tell them what to do, he says.

"Having said that, I think it still can be done if you can identify the really high-risk patients and do something about it," Goldfarb says.

Cincinnati pediatric nephrologist Goldstein is using electronic medical records to do just that. He says he got tired of consults that required him to repeatedly note "AKI secondary to NTMx [nephrotoxic medications], we will follow with you" in patient charts. He started to think that a simple, inexpensive creatinine test could be used to detect warning signs of the condition.

To be cost-effective, such a test would need to be targeted to pediatric patients most likely to develop kidney injury. Goldstein hypothesized that certain groups of patients were most at risk: those receiving the intravenous antibiotic aminoglycoside for more than three days and those who had been exposed to three nephrotoxic medications simultaneously. After a diagnostic database offered evidence supporting the elevated risk, the hospital's IT services programmed the hospital's electronic health records decision-support system to identify those patients so they could be screened.

With little prodding, doctors started to take note of dangerous changes in kidney functions and took steps to stave off AKI, he says.

The first year's 42% drop in AKI intensity—the number of days a patient has AKI before kidney function returns to baseline—translated into 900 patient days of AKI avoided in one year.

"What this program did was change nephrotoxic AKI from a necessary evil that we had to accept in treating complex patients to, in some cases, a potentially modifiable adverse safety event," he says. "Once you frame it that way, it takes on a whole different flavor."

Now, he hopes to share the lessons of this program with other hospitals. But, as with Goldfarb, Goldstein sees the need to get house staff to buy in. Pharmacists also are key to Goldstein's team. And efforts like these need support from the top.

"You absolutely have to have a hospital administration that believes there is a business case for quality," says Goldstein. That way, they will be willing to make the up front investment in information technology and pharmacy services.

The goal is to learn from the barrier he and his team had to overcome in Cincinnati.

"We basically want to make this a playbook so we can spread this to other hospitals."

Reprint HLR0814-10